Methods of and apparatus for twisting and stranding cable pairs in a tandem operation

ABSTRACT

A twist is imparted in each pair of a plurality of pairs of insulated conductors for each revolution of an associated flier bow as each of the pairs pass over sheaves at opposite ends of the bow in a high speed twister. Each of the twisted pairs is passed from the twister along a predetermined path through an associated untwist-retwist device in which the twisted pair is untwisted by advancing successive sections of the individual conductors along separate paths and revolving the successive sections of the conductors being advanced along the separate paths about the predetermined path. Subsequent to the successive sections of the individual conductors of each of the untwisted pairs being moved away from the associated untwist-retwist device, a double twist is imparted to each pair in a uniform distribution. The plurality of retwisted pairs are moved immediately into a strander to form a cable having a binding applied thereto to thereby retain the uniform distribution of twist.

llnite States atent 1 Crotty et al.

[54] METHODS OF AND APPARATUS FOR TWISTING AND STRANDING CABLE PAIRS IN A TANDEM OPERATION [75] Inventors: Francis N. Crotty; William C. Gause; George E. Hartranft, all of Baltimore, Md.

[73] Assignee: Western Electric Company, Incorporated, New York, NY.

[22] Filed: June 29, 1971 [21] Appl. No.: 157,947

[52] U.S. Cl. ..57/59, 57/58.52, 57/62,

57/156, 57/160, 57/66 [51] Int. Cl ..Hlllh 13/00, IIOlb 1 3/04 [58] Field of Search ..57/3, 9-19,

[11] 3,732,682 1 May 15, 1973 FOREIGN PATENTS OR APPLICATIONS 701,119 3/1931 France ..57/59 822,119 11/1951 Germany ..57/62 PrimaryExan ineF-Donald E. Watkins Attorney-W. M. Kain, et a1.

57 ABSTRACT A twist is imparted in each pair of a plurality of pairs of insulated conductors for each revolution of an associated flier bow as each of the pairs pass over sheaves at opposite ends of the bow in a high speed twister. Each of the twisted pairs is passed from the twister along a predetermined path through an associated untwist-retwist device in which the twisted pair is untwisted by advancing successive sections of the individual conductors along separate paths and revolving the successive sections of the conductors being advanced along the separate paths about the predetermined path. Subsequent to the successive sections of the individual conductors of each of the untwisted pairs being moved away from the associated untwist-retwist device, a double twist is imparted to each pair in a uniform distribution. The plurality of retwisted pairs are moved immediately into a strander to form a cable having a binding applied thereto to thereby retain the uniform distribution of twist.

43 Claims, 18 Drawing Figures PATENTEB HAY] 5 I975 SHEET 1 OF 9 WC. GAUSE M N A m A H, E 6

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PATENTEb MY 1 5l975 SHEEI 5 [IF 9 PATENTED HAY] 51975 SHEET 8 UP 9 PATENTEI] HAY] 51975 SHEET 7 [1F 9 PATENTED HAY] 51973 SHEET 8 OF 9 OWN PATENTED 3,732,682

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1 METHODS OF AND APPARATUS FOR TWISTING AND STRANDING CABLE PAIRS IN A TANDEM OPERATION BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to methods of and apparatus for twisting and stranding cable pairs in a tandem operation, and, more particularly, to methods of and apparatus for twisting each of a plurality of cable pairs at a different twist length and for then removing the twist therefrom and subsequently retwisting and stranding the cable pairs in a tandem operation.

2. Technical Considerations and the Prior Art The development of improved transmission systems employing higher frequencies and gain devices has been limited by existing multi-pair cable capabilities. In designing cables for present communications needs, there has been an increasing need for producing cables with both low loss and low far end crosstalk. Also, crosstalk and loss determine to a large extent the maximum repeater spacing that can be used in a system.

In the manufacture of cables for use in the telephone industry, it has been deemed desirable tointertwist a pair of individually insulated conductors to form a twisted pair. It has been found that the problems in communications cables which are associated with crosstalk can be overcome by imparting a twist to the pair of individually insulated conductors.

The art has defined twist length to mean the length required for a point on one of the conductors of the twisted pair to complete a 360 spiraling cycle and be in the same relative position with respect to theother conductor of the twisted pair as exists at the starting point of the cycle. For a description and drawing of what is referred to as right-hand twist and left-hand twist, reference is made to U.S. Pat. No. 3,052,079, issued Sept. 4, 1962 in the name of George R. Henning. A right-hand twist is defined to refer to a conductor pair which is twisted so that an observer looking along the pair from a vantage point at a cross section thereof observes the conductors spiraling in a clockwise direction. A left-hand twist refers to a spiraling in a counterclockwise direction.

The intertwisting of the insulated conductors to form a twisted pair-may be accomplished in a process in which the conductors are twisted together continuously to form a unidirectional twist therein. In carrying out the steps of this process, either the conductor supply or the takeup is usually rotated about the longitudinal axis of the conductors in the forming of the unidirectional twist.

A typical strand twisting apparatus is shown in U.S. Pat. No. 1,684,533, issued on Sept. l8, 1928, in the name of one G. A. Bouvier. There a cotton core and six tinsel served threads are passed in a first direction over sheaves and around a capstan of a twisting unit and from there in a reverse direction for a short distance. The core and tinsel are then advanced in the first direction downwardly and through a rotating flier arm to revolve successive sections of the strand about a vertical axis of the apparatus. After the successive sections emerge from the flier bow, the successive sections are advanced upwardly in the reverse direction and taken up on a reel inside of the surface of revolution generated by the flier bow.

A plurality of the twisted pairs of conductors are then fed into a strander, wherein the twisted pairs are associated together into stranded cable units. In the past, it has been customary to twist the individually insulated conductors together in a twisted pair in an operation distinct from the stranding operation.

Prior art high speed twisting machines have included reels which are each supported in a separate, stationary reel carrier. An arcuately formed tubular member, commonly referred to as a flier bow, is moved rotatably around these reel carriers to revolve the conductors being payed off from the supply reels about the axis of the machines. Machine lengths corresponding to the reel spacings, large weights and driving power and excessive reel assembly and machine set-up times have been necessary in using this conventional apparatus. The use of the hereinbefore-described twisting machines has also necessitated accurate balancing of large rotating masses and numerous bearings for the tubular members and reel carriers which give rise to a high noise level and requirements of undue amounts of supervision, maintenance and repair.

The output of prior art high speed twisting machines in which either the supply unit or the take-up unit is revolved has been limited by the speed of rotation which can be attained. The rate of rotation of the prior art machines, because of the effect of inertial forces, is determinative of the speed of twisting of the machine. The supply unit containing the reels wound with insulated conductors or pairs or quads or units for forming the cable are large and heavy as is the support equipment. The winding unit including the take-up device for the pairs or quads, units or cable core is also large and bulky, with the result that it is difficult to increase the twisting and/or take-up of these prior art apparatus.

Another problem in twisting occurs because of the manner in which the twist is imparted to pairs of conductors in a conventional apparatus. Conventionally, a pair of strands are fed from individual supply reels in a first direction and subsequently in a second direction, and passed over guide sheaves which are orbited collectively about a common centerline. The orbiting is not the rotation of each individual sheave about the sheave axis, but rather an orbiting effect of the sheaves about the centerline as if all the sheaves were mounted on a common frame.

As the sheaves are orbited about the common centerline, a first twist is imparted to the pair of strands as the strands pass generally about a first sheave at one end of the flier bow. A second twist is imparted as strands are passed in the second direction and around another sheave at the other end of the flier bow. Therefore, two twists are imparted to given lengths of the pair of strands.

Since one twist is imparted to the pair of strands generally in the area of one sheave and the second twist imparted generally in the area of the second sheave, spaced from the first, the two twists per length are not uniformly distributed. Hence, when the twisted pair of strands is later stranded with a predetermined number of other twisted pairs to form a cable unit, the nonuniformity of the distribution of the twists results in undesirable effects when the cable unit is used in a communications network. Clearly, there is a need for imparting a more uniformly distributed twist to conductor pairs.

Accordingly, in an attempt to overcome some of the discussed prior art shortcomings, one patent (U.S. Pat. No. 3,431,718) provides a method of twisting which includes drawing a plurality of strands from supply reels which are mounted in a stationary reel carrier in the direction opposite to the direction of withdrawal of the end product. The strands are then guided through at least one guide unit around the exterior of the reel carrier, and passed in the direction of withdrawal of the end product to a twisting head and subsequently to a compression die where the twisting of the strands occurs. That patent discloses that the strands experience no intertwisting and no new intratwisting in their passage from the reel carrier to the compression die. The guide unit is rotated about the reel carrier and the twisting head rotated in the same direction but at double the speed of the guide unit, the guide unit guiding the strands from the reel carrier to the twisting head individually and separately from one another.

Additionally, in one recently issued U.S. Pat. No. 3,570,234, issued on Mar. 16, 1971 in the names of H. W. Freesin and W. F. MacPherson, facilities are provided to insure that the twist is always applied between precisely defined points, the exit end of a flier bow and a capstan. A flexible shaft with internal guides is submitted for the conventionally constructed flier bow, which permits the reel end of the shaft to be fixed. The shaft output end is rotated at twice the rotational rate of the shaft. Two smaller flexible shafts within the main shaft houses the conductors to be twisted. All of the twist occurs as the conductors exit from the free capstan end of the smaller shafts. However, there have been some problems of wear with some of the types of flexible shafts, for example, helically wound springs, which have been used.

In addition to imparting twist to associated pairs of individually insulated conductors to reduce crosstalk, in the manufacture of multiple pair cable, it is also the practice to apply differing length twist to adjacent pairs to reduce further the incidence of crosstalk. The neighboring or juxtaposed pairs of subassemblies in cable have different predetermined twist lengths to cause the members of one pair to reduce inductive disturbances, for example, crosstalk when the cable is used for telephone purposes, to a minimum.

This has required a predetermined number of different and distinguishable subassemblies, each having a different rate of twist or twist length and requires that each pair be identified. It has also required that the pairs be located in a predetermined relation in the cable and that these positions be maintained. This has required the manufacture and storage of a number of different subassemblies and particular care in the selection and assembly into the cable, which, of course, adds to the cost of the cable.

At least one prior art patent (U.S. Pat. No. 2,956,102) provides a single twisted pair having the lengths of the twists in the pair continuously varying throughout. Preferably random variation is controlled so that there is no fixed pattern in the twist variation whereby lengths of the one twisted pair can be placed adjacent one another in open circuits or in cables with a minimum of difficulty from inductive disturbances therebetween.

An invention disclosed in U.S. Pat. No. 3,546,357, issued Dec. 8, 1970, is addressed to a conductor twist configuration which permits both attenuation deviation and crosstalk deviation to be maintained at low levels. Also, an apparatus will continuously produce stranded twisted conductors conforming to that twist configuration and indeed to substantially any twist characteristic that might be desired. A plurality of conductor pairs are continuously twisted and thereafter stranded with the twist length for each pair being fully controllable.

There is still a need for non-complex and relatively inexpensive and generally simplified apparatus for imparting twist to conductor pairs of a cable unit such that adjacent conductor pairs have different twist lengths.

Although certain improvements have been made with regard to twisting, increasingly demanding standards with regard to improved crosstalk characteristics can be achieved by employing relatively short pair twists, i.e., on order of one inch. However, the difflcul-' ties in balancing and in maintaining large rotating masses are only amplified when the higher rotational speeds required to impart shorter twist lengths are used. The requirement for shorter twist lengths further points up the need for the innovation of manufacturing processes and equipment having the capability of imparting a uniformly distributed twist to a conductor pair.

In some prior art methods, the process for providing pairs of quads of twisted pairs is done in one operation and the stranding of the units into a cable done separately, which contributes to the non-uniformity of twist in conductor pairs. In the manufacture of communications cables, stranding is one of the most important problems. Much thought has been given to increasing the stranding speed and tandemizing the process for twisting insulated wires into a pair or quad with the process for stranding a plurality of the pairs.

Prior art stranding methods have included rotating a cage provided with a plurality of supply reels of conductor pairs to strand the pairs to a take-up reel. There has also been used a strander in which the axes of the supply reels are stationary while the entire take-up device is rotated. Finally, the pairs of conductors may be payed off or taken around the supply or the take-up device with a flier.

The first-mentioned apparatus creates a large centrifugal force because of the rotation of the cage and reels so that the revolutions per minute is somewhat limited with accompanying low stranding speed. Undue time is also required to load and unload supply reels into the cage. The second-mentioned prior art strander permits of high speeds, but much time is consumed in loading and unloading a take-up reel. Moreover, it is impossible with this apparatus to continuously carry out the stranding of insulated conductors and stranding the twisted pairs in a tandemized operation. The third approach permits of high speeds but is somewhat inconvenient to load and unload the supply or take-up reels.

The twisting and stranding is preferably done in a tandem operation to help insure that the twist is maintained precisely located and in a uniform manner. The need for reeling and unreeling of twisted pairs, which distorts the twist in a pair, is eliminated. Intermediate handling and storage is eliminated. Tandem twisting and stranding offers several other important advantages. Tandem twisting and stranding greatly reduces the number of sheaves over which the twisted pairs pass with accompanying distortion of twist.

It is believed that some of the problems alluded to can be overcome by (l) inducing the desired amount of twist at one point and (2) twisting and stranding in tandem. Of course, if the amount of twist were induced at one point by say advancing a pair of parallel conductors from supply reels to a twister head, the conductor pairs would twist before and after the twister head. This would result in a breaking of the conductors as the twists accumulate on the upstream side of the twister head.

Therefore, in order to impart the desired twist to a conductor pair at a single point, it is necessary to supply the conductor pairs to the twister head in an already twisted condition. The twister head must then be run at a speed which is twice the speed of the flier used to impart the initial twist into the conductor pair so that the conductor is first untwisted before retwisting.

In one prior art apparatus, a twist setter operates on this general principle. With some conductors, the wire is made of a material such that when twist is imparted thereto, the wire has an inherent tendency to untwist. Therefore, it has been the practice to advance a twisted pair around a rotatably mounted sheave which is revolved about the axis of the advancing conductor and to then pull the conductor from the sheave by a capstan. Depending on the relationship of such factors as line speed and speed of revolution of the sheave, the initial twist may be completely removed and then reset thereby working the twisted pair to set the twist. In devices such as this, the conductors of the twisted pair remains together or as adjacent conductors as the pair are advanced around the sheave and out of engagement therewith, the sole purpose being to set the final twist in the conductors.

This principle is shown, for example, in U.S. Pat. No. 1,671,951, issued on May 29,1928, now RE 18,142, in which a drum having several turns of a strand wrapped therearound is mounted for rotation on an axis transverse of the lineal movement of the strand and having the peripheral surface thereof in tangential relation with respect to the lineal axis of the strand. The drum is also mounted to be revolved about an axis of revolution, the strand or all of the fibrous components thereof being intact as a unit throughout the advance thereof.

Other prior art of background interest to this invention may be found in the area of false twisting and twisting of yarn. For example, in U.S. Pat. No. 2,256,436,

issued on Sept. 16, 1941, there is shown a tubular spindle for receiving a twisted yarn from a pair of roller nips for carrying the yarn with the spindle through a constructed portion thereof as the spindle is rotated. A second pair of rollers nips the roving near the outlet of the spindle. In order to prevent the twists, which are left hand and right hand, from mutually eliminating each other, the rotary motion of the spindle is stopped periodically. The duration of these stoppages is adjusted to deliver a length of roving equal to the distance between the two pairs of rollers between which the spindle is mounted.

In another prior art patent (U.S. Pat. No. 2,655,781) there is shown an apparatus for imparting false twist to yarn. A yarn which is twisted between two pairs is advanced through a device which untwists the yarn so as to stress relieve the yarn. False twist is also imparted to yarns to preserve the yarn intact during various steps of the process to prevent in inherent untwisting from occurring. Contrasted to yarns, there is no inherent tendency on the part of conductor pairs to untwist. Any twist-untwist'retwist process is designed to achieve uniformity of distribution of twists. Moreover, the twistuntwist-retwist of conductor pairs in manufacturing communications cable is caused to occur along an axis mutual to both of the conductors of the pair.

There are other problems that must be overcome before realizing tandem twisting and stranding. Since a single twist unit is so bulky and requires such particular balancing, certainly if a number of pairs were to be simultaneously twisted and stranded, the problems with one twist unit could be cumulative. The priorly used high-speed twisting apparatus must be fashioned to reduce mass when a plurality of pairs are to be twisted simultaneously.

SUMMARY OF THE INVENTION An object of this invention is to provide methods of and apparatus for twisting and stranding cable pairs in a tandem operation.

It is also an object of this invention to provide methods of and apparatus for manufacturing a communications cable having a plurality of conductor pairs, each of the conductor pairs being twisted together with a uniformly distributed precise twist, and with adjacent conductor pairs having different twist lengths.

It is also an object of this invention to provide methods of and apparatus for twisting successive sections of a pair of conductors and subsequently advancing the individual conductors along separate paths while removing the twist therefrom and then reassociating the individual conductors into a twisted pair with a uniformly distributed twist.

A method illustrating certain features of this invention may include the steps of advancing successive sections of each of a plurality of strand materials along an associated predetermined path, imparting a twist to successive sections of portions of each of the plurality of strand materials while advancing each of the strand materials along the associated predetermined path, disassociating the successive sections of the twisted portions of each of the strand materials while removing the twist therefrom, retwisting together the successive sections of the portions of each of the strand materials, and stranding together the successive sections of the plurality of strand materials.

An apparatus for twisting and stranding cable pairs in a tandem operation and illustrating certain features of the invention may include facilities for advancing successive sections of each of a plurality of strand materials along an associated predetermined path, facilities for imparting a twist to successive sections of portions of each of the plurality of strand materials while advancing each of the strand materials along the associated predetermined path, facilities for disassociating successive sections of the twisted portions of each of the strand materials and for removing the twist therefrom, facilities for retwisting'together the successive sections of the portions of each of the strand materials, and facilities for stranding together the successive sections of the plurality of strand materials.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an apparatus which embodies the principles of this invention and includes facilities for imparting a uniformly distributed twist to conductor pairs and for then stranding the twisted pairs into a cable unit;

FIG. 2 is a side-elevational view of a portion of the twisting facilities of the overall apparatus and which includes a plurality of twisting units mounted between spaced flanges, each of the units including a cradle designed to supply a conductor pair to be twisted;

FIG. 3 is an enlarged detail view of a portion of a loading platform and safety step-plate;

FIG. 4 is a top view of one of the plurality of twisting units including the associated cradle which are used to support supply reels for twisting a conductor pair;

FIG. 5 is a view in elevation partially in section of the cradle of FIG. 2 and includes conventional apparatus for the high speed twisting of a conductor pair;

FIG. 6 is an enlarged detail view in section of a flier bow associated with each of the twisting units;

FIG. 7 is an enlarged detail view taken along lines 7-7 in FIG. 2 and showing facilities for driving the twisting units and untwist-retwist devices;

FIG. 8 is a perspective view of another portion of the apparatus and which includes a plurality of untwistretwist devices, each thereof being associated with one of the twisting units and associated supply cradles;

FIGS. 9A-9C are enlarged detail views of different ones of the devices which may be used to disassociate successive sections of the conductors of a twisted pair to remove an initial twist from a conductor pair and for then imparting a uniformly distributed twist to the conductor pair;

FIG. 10 is an enlarged detail end view of one of the untwist-retwist devices shown in FIG. 7;

FIG. 11 is an enlarged detail view of the portion of the apparatus just downstream of the untwist-retwist devices and showing a plurality of twisted pairs, each pair having a different length twist;

FIG. 12 is a view in elevation of a binding device which is used to apply a double binding to a stranded cable unit;

FIG. 13 is a detail view of improved facilities for guiding the stranded and bound cable unit into a capstan.

FIG. 14 is an end elevational view partially in section of a take-up device for taking up the successive sections of the cable unit;

FIG. 15 is a schematic view showing one of the conductor pairs being twisted, separated and untwisted, and retwisted as the conductor pair is advanced through the tandemized twisting-stranding operation; and

FIG. 16 is a schematic view of the separate paths of the conductors about the untwist-retwist device.

DETAILED DESCRIPTION General Arrangement Referring now to FIG. 1, there is shown an apparatus, designated generally by the numeral 20, for tandemized twisting and stranding of cable pairs of conductors. The general arrangement includes a twisting drum, designated generally by the numeral 21, for imparting continual twist to a plurality of pairs of strands or conductors 22-22 into twisted pairs 23-23, untwist-retwist facilities, designated generally by the numeral 24, stranding and binding facilities, designated generally by the numeral 25, for stranding and binding the plurality of conductor pairs into a cable unit 26, and a take-up, designated generally by the numeral 27, for taking up the cable unit. The stranding facilities 25 include a binding unit, designated generally by the numeral 28, for binding together the conductor pairs 23-23, and a rotatably mounted capstan, designated generally by the numeral 29.

It will be convenient in describing certain portions of the apparatus 20 and in describing the method of operation thereof to use the descriptive terms upstream" and downstream. This should be construed to refer to the general order of equipment beginning with the twisting drum 21 to the take-up device 27 and the general direction of flow of the cable unit 26 in order of manufacturing sequence.

Twisting Drum As can best be seen in FIGS. 1 and 2, the twisting cage or drum 21 includes a pair of spaced apart flanges 31a and 31b which are connected by tie rods 32-32 spaced evenly about a circumferential circle of the flanges. In order to mount the twisting drum 21 for rotation, the flange 31a is supported on spaced rollers 33-34. One each of the rollers 33 and 34 which are positioned on the same side of the drum 21 are connected through a drive 36 to a drive motor 37. The rollers 33-33 and 34-34 are supported on ledges within a well 38 which opens to a manufacturing floor 39. The remainder of the equipment as shown in FIG. 1 is mounted on the manufacturing floor 39.

The twisting drum 21 is enclosed by a wire mesh covering 42 to protect operating personnel during the twisting operation. Additionally, the top most half of the twisting cage has a solid transparent cover 43, made from a material such as transparent Lexan, over the wire mesh fabric 42 to afford protection against small lengths of the conductors 22-22 that may be directed centrifugally outwardly from the twisting cage at high velocities. The cover 43 is also effective in reducing the noise level of the apparatus 20.

In order to load the twisting drum 21 with a plurality of supply reels 44-44 having conductors 22-22 wound thereon, arcuate segments of the wire mesh fabric 42 and overlying cover 43 are mounted for rotational movement. After rotation of the drum has ceased, the segments of the mesh fabric 42 and overlying cover 43 may be moved to expose the interior of the drum. Additional safety features are provided to afford protection during the loading of the supply reels 44-44.

The mounting of the twisting drum 21 on the rollers 33-33 and 34-34 exposes a gap between the tie rods 32-32 and the top surface 46 of a loading platform 47 (see FIGS. 1 and 3). In order to avoid having an operator stretch across the opening during loading, a floor plate 48 is attached to each of the tie rods 32-32 to span across the gap and be contiguous to the top surface 46 of the loading platform 47 (see FIG. 3). Moreover, the plate 48 is spring-loaded with a resilient pin 49. Then, if an object is inadvertently placed between the plate 48 and the platform and should the drum 21 be rotated in a counterclockwise direction as viewed in FIG. 3, the plate merely is urged in a clockwise direction toward the drum, thus avoiding shearing off the portion of the protruding object. If the drum 21 were to be rotated in a clockwise direction as viewed in FIG. 3, the overhanging object would be merely upended. Twisting Units The twisting drum 21 supports a plurality of twisting units, designated generally by the numerals 51-51 (see FIGS. 2, 4 and 5), which simultaneously twist each of the plurality of conductor pairs 23-23 which are later untwisted and retwisted and then stranded into the cable unit 26. Each of the twisting units l51 includes a cradle 52 having facilities for supporting two of the supply reels 44-44 having conductors 2222 wound thereon.

Each one of the cradles 52-52 includes a pair of spaced apart side plates 53-53 connected at the ends thereof by end plates 54-54. In order to support the reels 4444 when the reels are positioned between the side plates 5353, two pair of spaced rods 56-56 and 57-57 (see FIG. 5) span between and are connected to the side plates. When the reels 44-44 are placed between the side plates 5353, the flanges of one of the reels are supported on the rods 5656 while the flanges of the other one of the reels are supported on the other pair of the rods 5757.

Provisions are made to support each of the reels 4444 rotatably within each of the cradles 52-52. Aligned with each pair of the rods 56-56 and 5757 are a fixed support cone 58 and a movable support cone 59 (see FIG. 4) which are designed to be received in the hub openings of the reels. The center lines of the cones 58 and 59 are aligned and spaced above the rods 5656 and the rods S7-57 so that when the reels 44-44 are supported by the cones, the flanges are slightly above the associated rods 56-56 or 57-57 (see FIG. 5).

In order to move the reels 4444 off the associated rods 5656 and 5757, each one of the movable cones 5959 has a handle 61 extending laterally of the axis thereof. The handle 61 is turned to follow a cam race 62 formed in a bushing 63 mounted externally of one of the side plates 5353. The turning of the handle 61 moves the associated movable cone 59 inwardly to advance the movable cone into the one hub opening (not shown) in the flange of the reel 44 which is adjacent the movable cone. Continued movement of the movable cone 59 urges the walls of the other one of the hub openings into engagement with the fixed cone 58 until the fixed cone is received in the other hub opening and the reel 44 is supported rotatably between the movable cone and the fixed cone.

Provisions are also made for driving individually the supply reels 44-44. As can best be seen in FIGS. 4 and 5, each of the supply reels 44-44 has a drive system 64 associated therewith. Each of the supply reels 4444 is connected to the drive system 64 by an associated friction plate 66 which is adapted to engage the flange of the reel which is adjacent the fixed cone 58.

Referring now to FIGS. 4 and 5, there are shown the paths of the conductors 22-22 which are withdrawn from the supply reels 44-44 in one of the twisting units 51-51. The conductor 22, designated 22a from the downstream one of the reels 4444 is passed over a sheave 67 and thence over a sheave 68 which is below the sheave 67. The sheaves 67 and 68 lie generally in a plane which is canted to the vertical. Then the conductor 22a is passed in a downstream direction around a sheave 69 having a generally vertical axis 71 and then back in an upstream direction through an opening 72 in the end plate 54 of the cradle 52.

Similarly, the other one 22b of the conductors from the downstream one of the supply reels 44-44 is withdrawn from the reel and passed over a pair of sheaves 73 and 74 which lie in a plane canted to the vertical and angled to the aforementioned plane containing the sheaves 67 and 68. The conductor 22b is then directed in a downstream direction around a sheave 76 having a generally vertical axis and then in an upstream direction through the opening 72.

Provisions are made for controlling the tension of the conductors 2222 being payed out from the reels 4444. As can best be seen in FIG. 4, each of the sheaves 69 and 76 is mounted rotatably and for arcuate movement in a generally horizontal plane on one end of an arm 77. The arm 77 is mounted for pivotal movement about a pin 78 and has a gear segment 79 mounted between the associated one of the sheaves 69 or 76and the pins 7878. The gear segment 79 is in meshing engagement with a gear 81 that is mounted on a shaft extending from a rheostat 82.

The rheostat 82 is connected through a circuit (not shown) to the drive system 64, mounted adjacent one of the side plates 53-53. The drive system 64 associated with each one of the reels 44-44 is responsive to changes in the tension of the associated conductors 22-22 being payed out from the reels manifested in rotation imparted by the gear segment 79 to the gear 81 and hence to the rheostat 82. The turning of the rheostat 82 controls the electrical circuit (not shown) to increase or decrease the rotational speed of the friction plate 66 and hence to increase the rotational speed of the reels 4444.

The conductors 2222 are advanced through the opening 72 and through a passageway 83 in a guide bushing 84 that is mounted rotatably in a bearing 85. The bearing 85 is mounted in a support 86 connected to the end plate 54. As can be seen in FIG. 5, the conductors 2222 are advanced around a sheave 87 and then around a sheave 88 which are supported rotatably between a pair of plates 8989 of an end support or carriage 90. The plates 8989 on the downstream side thereof are connected to the bushing 84 and the upstream side of the plates are connected to a pintle 91.

Each one of the cradles 5252 is supported at the downstream end thereof in a fashion similar to that just described for the upstream end. The downstream one of the end plates 54-54 is connected to a bracket 92 having a bearing 93 mounted therein. A stub shaft 94 extends into the bearing 93 and is attached to a cross plate 96 spanning and connected to two spaced plates 97-97 of a support 98. The plates 97-97 are attached to a downstream pintle 99.

It should be observed from this arrangement of a typical one of the cradles 52-52, that the cradle is freely supported or free floating as between the bearings 85 and 93. In this way, the pintles 91 and 99 may be driven rotatably as is to be later described to move rotatably the supports and 98 about an axis 101 without imparting rotation to the cradle 52.

Facilities are provided for moving successive sections of the conductors 2222 from the upstream support 98 while revolving the successive sections of the associated conductors 2222 about the axis 101 of the associated cradle 52. More specifically, the successive sections of the conductors 2222 are moved from the sheaves 87 and 88 in the upstream support 90 into engagement and around successively a sheave 102 and a sheave 103 which are mounted rotatably between the plates 97-97 of the support 99. As can best be seen in FIG. 5, a flier bow, designated generally by the numeral 106, is connected to a bearing 107 mounted rotatably between the plates 97-97 of the downstream support 98.

Referring now to FIG. 6, it can be seen that the flier bow 106 includes an arcuately formed metal strip 109 having a plurality of crossheads 111-111, spaced therealong. Each of the crossheads 111-111 is a generally rectangular block having two peripherally located holes 112-112 and a central hole 113 formed therethrough. Two wire ropes 114-114 extend from the bearing 107 to the bearing 108, each of the wire ropes being threaded through the holes 112 on each side of each of the crossheads 111-111.

This construction is an improvement over prior art flier bows such as that shown in US. Pat. No. 1,684,533, issued on Sept. 18, 1932. The flier how 106 is similar to that shown in the above-mentioned patent but includes the metal strip 106. The metal strip 106 is useful in preventing collapse of the flier bow 106 after the rotation thereof about the axis 101 has been discontinued.

The conductors 22-22 are passed from the sheave 88 through a passageway 116 in the bearing 107, then through successive ones of the aligned holes 113-113 in the associated successive ones of the crossheads 111-111 and through a passageway 117 in the bearing 108 in the downstream support 92. Then the conductors 2222 are passed around the sheaves 102 and 103 and through a longitudinal bore 118 formed in the pintle 99.

It should also be observed from FIGS. 2 and that each of the twisting units includes two of the flier bows 106-106. The one of the flier bows 106-106 hereinbefore described revolved successive sections of the associated conductor pairs about the axis 101 of the twisting unit 51. The other one of the flier bows 106-106 is identical in construction, but is used merely for purposes of balancing the twisting unit 51. Arrangement of Twisting Units The embodiment of the apparatus shown in FIG. 1 is designed to twist individually seven pairs of conductors 2222 and then to strand the seven conductor pairs 29-29 into a cable unit 26. In order to accomplish this, seven individual twisting units 51-51 are required.

It may be observed from FIG. 1, that six of the seven twisting units 51-51, designated 51a-5lf for convenience, which form six of the seven conductor pairs 23-23 of the cable unit 26 are arranged equidistantly about a centerline axis 119 of the twisting drum 21. The centerline axis 119 is generally perpendicular to the flanges 31a and 31b. Each of the twisting units 51-51 within the twisting drum 21 is separated from the adjacent ones of the twisting units by a separator plate 121. The separator plates 121-121 are connected between the flanges 31a and 31b and extend radially outward from the axis of rotation 119.

The six twisting units 51-51 within the drum 21 are arranged so that the associated axes 101-101 thereof are in converging engagement with the axis 119 of the drum 21 at a point downstream of the flange 31b.

The seventh one of the twisting units 51-51, designated 51g, is positioned adjacent the upstream flange 31a of the twisting drum 21 (see FIG. 1) and designed to have the twisted pair advanced therefrom along the axis 119 of .the drum. The upstream and downstream supports 90 and 98, respectively, of the seventh one of the twisting units 51-51 are mounted from stands 122-122 supported on the manufacturing floor 39. The conductors 2222 to which twist is imparted by the seventh twisting unit 51 are advanced through the passageway 118 in the downstream pintle 99 and thence through a tube 123 (see FIG. 7) concentrically disposed within a tie rod 124 and about the axis 119. The tie rod 124 extends through a bearing 126 in an opening 127 in the drum flange 31a, and thence through a bearing 128 in an opening 129 in the downstream drum flange 31b.

Drive System Referring now to FIG. 7, there are shown portions of a system, designated generally by the numeral 130, for driving the individual ones of the twisting units 51-51 and for driving additional facilities to be described hereinafter which are effective to untwist and retwist the conductors 2222. A main gear 131 is connected to a drive motor (not shown) and is mounted inside of an enclosure 132 on the upstream side of the flange 31a of the twisting drum 21. The centermost one of the tie rods 124-124 extends through a center opening in the gear 131 and through a bearing in the enclosure 132 (see FIG. 7).

The main gear 131 is mounted for meshing engagement with a gear 133 that is mounted on a shaft 134. Also mounted on the shaft 134 is a gear 135 which is connected through a gear train having an end gear 136 thereof mounted on a shaft 137. The shaft 137 also has a change gear 138 mounted thereon which is in meshing engagement with another change gear 139.

Referring again to FIG. 7, it can be seen that the change gear 139 is mounted on a shaft 141 having a transmitting gear 142 also mounted thereon. The gear 142 is in meshing engagement with a bevel gear 143 connected to a drive shaft 144 which extends through the flanges 31a and 31b of the twisting drum 21 and is mounted in bearings 146 and 147, respectively, in the flanges. The drive train shown in FIG. 7, starting with the gear 133 through the bevel gear 143, is repeated six times about the axis 119 of the twisting drum 21, once for each of the individual twisting units 51-51. Each set of the change gears 138 and 139 is accessible through an associated access door so that the rotational speeds of each of the twisting units 51-51 may be changed as desired.

The gear 131 is designed to impart motion simultaneously to each of the six twisting units 51-51 arranged about the twisting drum 21. At the upstream end of the drive shaft 144, the drive shaft is supported in a bearing 148 with an end of the drive shaft having a pulley 149 connected thereto. The drive shaft 144 is connected to the upstream pintle 91 of the associated twisting unit 51 by a belt 151. The belt 151 is passed around the pulley 149 and a pulley 152 attached to a shaft 153 extending from the associated pintle.

This arrangement provides facilities for driving the upstream end of the twisting unit 51 and specifically the associated flier bow 106. Problems could arise if only one end of the flier bow 106 were driven. For example, a certain amount of torsion could be imparted to the flier bow 106 which may possibly cause adverse effects on the flier bow itself as well as the performance thereof.

In order to overcome this problem, provisions are made for driving both ends of each of the flier bows 106-106. A pulley 154 connected to the downstream end of the drive shaft 144 supports a belt 156 which is passed therearound to a pulley 157 which is attached through a shaft 158 to the downstream pintle 99 of the associated twisting unit 51. Similar provisions (not shown) are made for driving both ends of the flier bow 106 of the twisting unit located upstream of the flange 31a and outside of the twisting drum 21.

The drive system 130 hereinbefore described is used to drive not only the twisting unit 51-51 but also todrive the untwist-retwist units 24-24 which are located downstream of the twisting drum 21. As can best be seen in FIG. 7, the shaft 158 also has a pulley 161 attached thereto for supporting a belt 162 which is passed over a pulley 163 that is mounted rotatably on a support shaft 164. The support shaft 164 also has a pulley 166 attached thereto for supporting a belt 167 which is passed around a pulley 168 that is connected to an end part 169 of an elongated tubular guide member 171. The twisted pair 23 of conductors 22-22 are passed through the downstream one 99 of the pintles and into the aligned associated one of the tubular members 171-171 (see FIG. 7).

The drive arrangement exemplified by the pulley 161 through belts 162 and 167 to pulley 168 permits the tu bular guide member 171 to be driven at a rotational speed which is greater than the rotational speed of the associated flier bow 106. In order to achieve an untwisting and subsequent retwisting of each of the conductor pairs 23-23, it has been determined that the rotational speed of each of the tubular guide members 171-171 must be twice that of the rotational speed of the associated ones of the flier bows 106-106. The actual untwisting and subsequent retwisting of the conductor pairs 23-23 is accomplished downstream of the twisting drum 21.

The drive system 130 hereinbefore described permits not only a change in rotational speed of the drive shafts 144-144, but also permits varying the rotational speeds as between the different ones of the drive shafts. Hence, the rotational speeds of the flier bows 106-106 may be different from each other to impart different length twists as between the seven conductor pairs 23-23.

The drive system 130 also includes a clutch (not shown) which permits the operation of each of the flier bows 106-106 and associated ones of the untwistretwist facilities 24 at the same rotational speeds to facilitate string-up of the conductors 22-22 at the startup of the apparatus 20.

Untwist-Retwist Facilities The twist imparted to the conductor pairs 23-23 by the associated twisting units 51-51 is removed therefrom and new precise, uniformly distributed twist imparted thereto by the untwist-retwist facilities 26 subsequent to the conductor pairs being moved downstream of the drum 21. In order to perform these operations, a plurality of untwist-retwist devices, designated generally by the numerals 181-181 (see FIGS. 1 and 2), are positioned downstream of the twisting drum 21 with each one of the untwist-retwist devices being associated and connected to one of the tubular guide members 171-171.

Referring now to FIG. 2, the tubular members 171-171 are supported rotatably in bearings 172 in upright plate 173, then in bearings 174 in a crosshead plate 176, and in bearings 177 in a crosshead plate 1'78. The crosshead plate 178 is just upstream from the plurality of untwist-retwist devices 181-181.

As can best be seen in FIGS. 8, 9A and 10, each of the untwist-retwist devices 181-181 includes a head 182 composed of a solid portion 183 having spaced side plates 184 and 186 extending therefrom. A sheave 187 having double grooves 188 and 189 is mounted rotatably on a pin 190 extending from the side plate 184, and a sheave 191 having double grooves 192 and 193 is mounted rotatably on a pin 194i extending from the side plate 186. Moreover, the solid portion 183 is constructed with a passage 196 formed therethrough for passing the conductors 22-22 of the associated conductor pair 23 from the associated tubular member 171 to the grooves 188-189 and the grooves 192-193.

Each one of the heads 182-182 is connected rigidly to the associated one of the tubular guide members 171-171. In this way, the heads 182-182 are rotated at the same speed as the associated ones of the tubular guide members which is twice the rotational speed of the associated ones of the flier bows 106-106. It is also to be noted that the rotation of the tubular guide members 171-171 and the heads 182-182 attached thereto is in the same direction as that of the associated flier bows 106-106.

As can best be seen in FIGS. 8 and 9, the conductors 22-22 of each of the conductor pairs 23-23 are separated upstream of the associated head 182 and are not rejoined in a twisted pair until at a point downstream of the associated heads 182-182. The point of separation may be as far upstream as the sheave 103 of the associated twisting unit 51 in the twisting drum 21. Moreover, each of the conductors 22-22 is advanced in a separate path through the associated head 182, the conductor 22a being advanced over sheave 191 in groove 192 and then over sheave 187 in groove 188 while the conductor 22b is advanced over the sheave 187 in groove 189 and then over the sheave 191 in groove 193. The sheaves 187 and 191 are mounted for orbital movement about the associated axis 101.

The separate path arrangement for each of the conductors 22a and 22b permits of a more effective untwist and more precise, uniformly distributed retwist than may have been accomplished in the past when the conductor pair 23 was simply advanced around a revolving sheave to set the twist therein.

The actual retwisting of each of the conductor pairs 23-23 is accomplished by the rotation of the heads 182-182 and accompanying revolving of the sheaves 187 and 191 in cooperation with a plurality of short tubes 206-206 positioned downstream of the heads 182-182. Each of the short tubes 206-206 is associated and aligned with one of the heads 182-182 and the attached tubular guide member 171. Moreover, each of the short tubes 206-206 is substantially greater in diameter than the diameter of the twisted pair 23 and has an enlarged upstream end 207. The short tubes 206-206 are mounted in a face plate 208 that is supported by a plurality of rods 209 cantilevered out from fixed connections with the crosshead plate 178.

It will also be observed from FIG. 8 that each of the tubes 206-206 protrudes a different distance upstream of the face plate 208 than that of the other one of the tubes. The final twist length imparted to each of the conductor pairs 23-23 is determined by the rotational speeds of the flier bows 106-106 and associated untwist-retwist devices 181-181 relative to the line speed.

It has also been found that a varying twist can be imparted to a conductor pair by varying the distance between the enlarged portion 207 of the tube 206 and the associated ones of the heads 182-182 of the associated untwist-retwist device 181-181. Accordingly, it is within the scope of this invention to mount the tubes 206-206 for reciprocal movement axially of the tubes 171-171. In this way, the drive system (not shown) for such an arrangement could be programmed so that the tubes 206-206 are moved reciprocally randomly to produce a randomly varying length twist along a conductor pair 23 to further reduce the crosstalk between the adjacent pairs of conductors.

After the conductors 22-22 emerge from the tubes 206-206 mounted in the faceplate 208, the conductors have been retwisted together into pairs 23-23 and the successive sections thereof are advanced axially of the tubes 171-171 into converging engagement with the stranding facilities.

The hereinbefore described portion of the method of this invention sets forth a rotation of each of the tubular members 171-171 and associated untwist-retwist devices 181 at twice the rotational speed of the associated one of the flier bows 106-106, i.e., twice the revolutions per minute. This arrangement provides, for example, a four inch twist imparted to a conductor pair 23 at the upstream end of the flier bow 106 and a four inch twist as the conductor pair enters the associated tubular guide member 171. A second twist in the 4 inch length which would normally occur at the downstream end of the flier bow is prevented from occurring because of the relative rotational speeds of flier bow and tubular guide member. After the conductor pair 23 in this example has been advanced through the associated untwist-retwist device, the conductor pair 23 has a two inch twist length.

Should the rotational speed of each of the untwistretwist devices 181-181 be less than twice that of the associated flier bow 106, the same length twist as that imparted at the upstream end of the associated flier bow 106 will be in the conductor pair 23 as the conductor pair exits from the twisting unit 51. However, in this instance, all of the twist will not be removed by the untwist-retwist device 181 and the conductor pair 23 will be caused to shear apart due to torsional stresses on the upstream side of the associated untwist-retwist device.

On the other hand, should this rotational speed of the untwist-retwist devices 181-181 be greater than twice that of the associated ones of the flier bows 106-106, i.e., ratio of speed of untwist-retwist device to that of associated flier bow is greater than two, all of the twist imparted by the flier bow 106 will be removed. Moreover, under these conditions, not only will all of the twist be removed, but the conductor pair 23 upstream of the untwist-retwist device 181 will be retwisted in the opposite direction. Eventually, the conductor pair 23 will shear apart as with the ratio of speeds less than 2, but in a direction opposite to that experienced when the ratio of speeds is less than two.

Although the untwist-retwist devices shown in FIG. 9A is the preferred embodiment and has been described in detail, the untwist-retwist device shown in 913 and 9C may also be used. In FIG. 9B is shown an untwist-retwist device 210 having a channel 211 with a plate 212 disposed therewithin. The plate 212 is upstanding and separates the conductors 22-22 of each pair 23, one of the untwist-retwist devices being associated with each of the conductor pairs. Referring now to FIG. 9C, there is shown still another untwist-retwist device 213 which includes a rotatablymounted spinner 213 having a pair of parallel spaced holes 214 drilled therethrough for separating and guiding the conductors 22-22 ofa pair 23. The spinner 213 is mounted for rotation about the axis 101 of the associated pair 23.

It has been found that the untwist-retwist device 181 shown in FIG. 9A appears to give the best results in terms of uniform distribution of twist. Attempts have been made to mount the sheaves along the associated axis 101, but results are improved by spacing the axes of the sheaves to each side of the axis 101 as is shown.

In each of the embodiments of the untwist-retwist devices 181-181, the conductors 22-22 of each pair 23 are disassociated by positively separating the conductors into diverging paths while the twist imparted by the associated flier bow 106 is removed. At least portions of the separate paths of each conductor pair 23 are spaced generally evenly circumferentially about the predetermined path or axis 101 of the twisting unit 51 which extends through the associated tubular guide member 171 and associated untwist-retwist device 181. Stranding Facilities The stranding facilities 25 include an entrance tube 216 having a flared end 217 to facilitate the advance of the conductor pairs 23-23 into the strander tube. Without a flared end, the conductor pairs 23-23 would be prone to be oriented in a random or fluctuating manner by engaging the peripheral end of the tube 216, resulting in variation in twist length. The twisted pair 23 would tend to be oriented with the valley between twist crests in engagement with the tube entrance. After a subsequent crest is advanced past the entrance, the pair 23 tends to turn to engage the next valley with the entrance rim. This results in a changing of the twist length and is overcome by using a flared entrance.

The entrance of the conductor pairs 23-23 into the flared end 217 of the stranding facilities 25 is best seen in FIG. 11. The tube 216 is mounted in a bracket 218. Additionally, FIG. 11 depicts very vividly the differing twist length as between adjacent ones of the conductor pairs 23-23.

The plurality of conductor pairs 23-23, which amounts to seven in the preferred embodiment shown in the drawings, are advanced downstream by the capstan 29. The capstan 29 is a commercially available piece of equipment and is designed to turn rotatably about the axis 119 of the apparatus 20. In this way, the capstan not only pulls the plurality of conductor pairs 23-23 through the binding unit 28, but also strands the pairs and imparts a lay thereto.

The plurality of twisted conductor pairs 23-23 are then advanced into the binding unit 28 of the stranding facilities 25. The binding unit 28 includes a binder device, designated generally by the numeral 220. As can best be seen in FIG. 12, the conductor pairs 23-23 are advanced through a constricted opening 221 in an entrance portion 222 of a hollow cop spindle 223. The hollow cop spindle 223 is supported rotatably in a bearing 224 in a block 226 that is mounted in a frame 227. The frame 227 is supported from a top surface 228 of a stand (see FIGS. 1 and 12).

In order to drive the cop spindle 223, a pulley 232 is attached to an enlarged end 233 of the cop spindle. A belt 234 is passed over the pulley 233 and connected to a drive system (not shown) through a clutch (not shown).

The cop spindle 223 includes a binder core 236 on which is mounted a binder cop 237 having a supply of binder 23d wound thereon. The binder 238 is to be payed off from the cop 237 and passed through an opening 239 of a cup 241 to be applied to successive sections of the stranded plurality of pairs of conductors 23-23.

The cup 241 is attached to a housing 242 that is mounted rotatably on bearings 2413 and 244 supported from the block 226. The cup 241 is driven rotatably at a constant angular velocity through a belt (not shown) which is connected to the housing 242 and to a drive system (not shown).

The drive system (not shown), which also drives the hollow cop spindle 223, has facilities for controlling the tension in the binder 233. By monitoring the comparative rotational speeds of the cop 237 and the cup 241, automatic compensation may be made for the difference in the speed of rotation of the binder cop as the binder 238 is payed out and the diameter of the cop is reduced. This results in the desirable condition or" maintaining constant tension in the binder 238.

The larger the package of the binder 238 on the cop 237, the lower the tension in the binder. Consequently, under these conditions, it is desired to apply more drag to the cop package. n the other hand, as the cop package 237 becomes smaller as more and more binder 23b is payed off and applied to the cable unit 26, the tension in the binder increases. In that instance, less drag must be applied to rotating cop 237 through the hollow cop spindle 223 in order to reduce the tension. The drag on the cop spindle 223 must be continuously reduced as the binder 238 is payed out to maintain a constant tension in the binder.

Two of the just-described binder devices 229-220 such as that shown in FIG. 12 are arranged in tandem to apply a double binder 238 spirally to the cable unit 26. The two binder devices 22619-229 are identical with an upstream one thereof arranged to apply the binder 238 prior to entry of the cable unit 26 into the hollow cop spindle 223 and with the other arranged down stream of the other to apply the binder as the cable unit exits from the hollow spindle 223 of the second binder unit.

The overall binder apparatus 220 has a pair of snubbing rollers 249 at the downstream end of the downstream one of the binder devices 229-220 (see H6. 12). The snubbing rollers 2d9-24l9 are spaced apart and mounted rotatably to grasp the cable unit 26 there-- between to prevent undue undulations in the cable unit due to the span between the binder apparatus 219 and the next successive in-line apparatus from affecting adversely the binding of the cable unit. Also, the snubbing rollers 2d9-249 overcomes the tendency of the cable unit 26 to twist as the second one of the binders is applied.

Although the binding apparatus depicted in FIG. 22 applied to two binders 232-238 in the same spiral direction by having the two binder devices 220-220 rotate in the same direction, the binders could be applied in opposite spiral directions in a basketweave pattern. Capstan After the cable unit 26, having two binders 238-233 applied thereto, is moved out ofthe binding unit 22, the cable unit is advanced through the capstan 29 (see FIG.

l The capstan 29 is a well-known tractor type having a pair of spaced closed loop-belts 251-2511 for grasping the cable unit 26 therebetween. The belts 251-251 are each mounted on a pair of spaced rollers 252 which are connected to a drive unit (not shown) for driving the belts. The capstan 29 is mounted rotatably between two uprights 253-253 ofa stand 254 and is connected through a hollow shaft 255 and pulley 256 by a belt 257 to a drive unit 253.

Provisions are also made to prevent the cable unit 26 from sagging during certain periods of the rotational cycle of the capstan 27. When the drive belts 251-251 are positioned so as to lie in generally vertical planes, the cable unit 26 tends to sag because of the distance between the capstan and the hollow shaft 255 (see FIG. 13). To overcome this, a small diameter tube 259 is positioned within the shaft 255 and extends to a point adjacent the belts 251-251 to reduce the unsupported span.

The capstan 29 not only pulls the twisted conductor pairs 23-23 from the tubular guide members ll71-ll7ll through the twister heads 182-182 and thence through the binder devices 229-220, but also is turning the twisted pairs rotatably to strand the pairs onto a cable unit 26, all in a tandem operation. A plurality of the cable units 26-26 may later be stranded into a larger cable unit. Following stranding, the cable unit 26 is taken up in the take-up device 27. Take-Up Device As can best be seen from FTGS. l and lid, the successive sections of the cable unit 26 are taken up on a reel 261 mounted rotatably in the take-up device 27. The reel 261 is supported for rotation between a fixed cone 262 and a movable cone 263 which are mounted internally of a large cylindrical enclosure 264 supported on the floor 39.

The movable cone 263 is mounted on an upper end of a threaded rod 266 that may be threadably turned into or out of a base 267 by a drive unit 268 to lower or raise, respectively, the movable cone 263. Another drive unit (not shown) imparts rotary motion to the reel 2611 to wind successive convolutions of the successive sections of the cable unit thereon.

The reel 261i is supported inside the enclosure 264 so that the axis of the reel is vertical and with the reel flanges horizontal. The enclosure 264i has an access opening 269 to facilitate unloading full reels 261-262 and loading of empty reels.

The access opening 269 is positioned to permit a pair of spaced forks 272-272 of a fork truck 273 to be in serted therethrough to move the forks under the lowermost one of the flanges of the reel 2611. During this maneuver, the forks 272-272 of the fork truck 273 straddle the movable core 263. The fork truck 273 is oriented with respect to the access opening 269 by a pair of spaced guide rails 27d-27d attached to the floor 39. Control System Although no electrical circuit is specifically disclosed, a sophisticated electrical control circuit is used to control interlocks of the safety features, wire tension controls and the start-up of the apparatus 2 1]). Also appropriate limit switches are included to stop the operation of the apparatus 20, should a conductor break or run out occur.

Method of Operation ln carrying out the method of operation for manufacturing a cable unit 26 in accordance with the principles of this invention, an operator loads a plurality of supply reels 44-44, each having an individual conductor 22 wound thereon into the twisting drum 21. The operator moves two of the supply reels 44-44 to the top of the platform 47 and controls the rotational movement of the twisting drum 21 through the electrical circuit (not shown) to position one of the twisting units 51-51 adjacent the platform 47. Then the operator causes the segments of the wire cage 42 and solid Lexan cover 43 to be rolled toward the opposite side of the twisting drum to expose the interior thereof and loads one of the supply reels 44 into the cradle 52 of the immediately adjacent twisting unit 51. The one supply reel 44 is positioned, say, in the downstream-most position in the cradle 52 with the flanges thereof resting thereof on the spaced rods 56-56 (see FIG. 4). Then the operator loads the other one of the reels 44-44 into the upstream one of the payoff positions to support the flanges of the reel on the spaced rods 57-57.

When the reels 44-44 are supported by the rods 56-56 and the rods 57-57, the reels are aligned with each pair of the fixed and movable cones 58 and 59. The operator then sequentially moves each of the handles 61-61 along the respective cam race 62 to move the associated movable cone 59 into the hub opening of the associated reel 44. As the movable cone 59 is advanced into the hub opening, the movable cone cams against the walls of the hub opening to urge the reel 44 to move up onto the associated fixed cone 58 until the reel 44 is supported on the fixed and movable cones. The operator then repeats the operation with the second one of the two supply reels 44-44.

Following the loading of the supply reels 44-66, the operator strings the conductors 22-22 as shown in FIGS. 4 and over the sheaves 67, 68 and 69 and the other one of the conductors over the sheaves 73, 74 and 76. Then the operator passes the conductors 22-22 through the opening 72 in the cradle 52 and through the passageway 83 in the bushing 84 and around the sheaves 87 and 88. The two conductors 22-22 are then passed through the passage 116 in the bearing 107 and then successively through each of the openings 113-113 in each of the crossheads 111-111 of the flier how 106. At the downstream end of the eradle 52, the two conductors 22-22 are passed through the passageway 117 in the bearing 108 around the sheaves 102-103 and then through the bore 118 in the pintle 99, through the twisting drum flange 31b. Finally, the two conductors 22-22 are pulled manually through the end part 169 and the associated tubular guide member 171 to the untwist-retwist device 181.

The operator then moves indexably the twisting drum 21 to position successively each one of the other five twisting units 51-51 inside the drum adjacent the loading platform 47 and proceeds to load two supply reels 44-44 into each one of the cradles 52-52 associated with the twisting units. Then the operator closes the drum 21 with the movable segments of the wire cage 42 and overlying solid cover 53. Additionally, the operator loads two supply reels 40-44 in the seventh one of the seven twisting units 51-51 which is positioned outside of and upstream of the twisting drum 21 and strings the conductors 22-22 through the central tube 123 extending through the drum 21 and then on through the central tubular member 171 to the associated head 182.

After the operator has completed the loading of the seven twisting units 51-51, the operator controls the initiation of the drive system to move rotatably each of the flier bows 106-106 and withdraw approximately 20 to 30 feet of the twisted pair of the conductors 22-22 from each of the twisting units 51-51. It should be observed that during the string-up procedure, the flier bows 106-106 impart two twists per length to each of the conductor pairs 23-23. The first one of the twists is imparted to each of the conductor pairs 23-23 generally as the conductors 22-22 thereof are passed around the sheave 87, while the second twist per length thereof is imparted generally to the conductors as the conductors are moved generally around the sheave 103.

Then the operator grasps successively each of the conductor pairs 23-23 of the conductors 22-22 and untwists the conductors until the twist is removed between the untwist-retwist facilities 24 and the twisting drum 21.

After all seven pairs 23-23 of the conductors 22-22 have been untwisted in such a manner, the operator strings up the untwist-retwist device 181-181 in a manner as shown in FIG. 16. As can best be seen in FIG. 9, one of the conductors 22a is passed under the sheave 191 in groove 192 and then around the sheave 188 in groove 189 and into the associated one of the short tubes 206-206. The other one 22b of the conductors 22-22 is first passed over the sheave 187 in the groove 189 and then around the sheave 191 in the groove 193 and into the same one of the short tubes 206-206. The conductor pair 23 is pulled through the associated short tube 206 and spliced to a conductor pair 23 extending upstream from the stranding facilities 25 and belonging to the previously stranded cable unit 26. The operator then performs a similar operation with respect to the other six conductor pairs 23-23 thus providing a setup for a continuous stranding operation in tandem with twisting.

The operator then controls the operation of the apparatus 20 to initiate operation of the capstan 29 of the twisting drum 21 and the take-up device 27. Reference is made to FIG. 15 which depicts the path of one of the conductor pairs and showing the manipulative steps performed with respect thereto.

Within each one of the twisting units 51-51, the conductors 22-22 are payed out from the supply reels 44-44 and pulled through the associated one of the flier bows 106-106. It should be realized that the twisting cage 21 is rotated only during the loading of the supply reels 44-44 and that the cradles 52-52 are mounted so as to remain substantially stationary as the flier bows 106-106 are revolved thereabout. Moreover, as can best be seen in FIG. 4, the sheaves 87 and 83 and the sheaves 102 and 103 associated with each one of the twisting units 51-51 are revolved in an orbital motion about the axis 101 of the twisting unit 51.

Should the tension in either one or both of the conductors 22-22 being payed out from the supply reels 34-44 be increased, the arms 77-77 tend to be pivoted toward the upstream end of the cradle 52 to cause the gear segments 79-79 to impart rotation to the gears 81-81 to turn the rheostats 82-82. The rheostats 32-82 control the drive systems 64-64 to increase the rotational speeds of the supply reels 44-44 to reduce the tension. Should the tension be reduced, the levers are spring-biased toward the downstream 

1. A method of tandemized twisting and stranding indefinite lengths of strand materials, which includes the steps of: advancing successive sections of each of a plurality of strand materials along an associated predetermined path; imparting a twist to successive sections of portions of each of the plurality of strand materials while advancing portions of each of the strand materials along the associated predetermined path; disassociating the successive sections of the twisted portions of each of the strand mateRials while removing the twist therefrom; retwisting together the successive sections of the portions of each of the strand materials; and stranding together the successive sections of the plurality of strand materials.
 2. The method of claim 1, wherein the disassociating and retwisting includes the steps of: moving successive sections of the portions of each of the strand materials along a separate path, at least portions of the separate paths of the portions of each of the strand materials being spaced generally equally circumferentially about the associated predetermined path; revolving the successive sections of the portions of each of the strand materials being advanced along the separate paths about the associated predetermined path to remove the twist therefrom; while converging the successive sections of the portions of each of the strand materials in a downstream direction to cause a retwisting of the successive sections of the portions of each of the strand materials.
 3. A method of twisting and stranding indefinite lengths of strand materials in a tandem operation, which includes the steps of: advancing successive sections of each of a plurality of at least two associated elongated materials along an associated predetermined path; imparting a twist to each of the plurality of successive sections of the at least two associated elongated materials about a mutual axis to form a plurality of twisted strand materials; disassociating the successive sections of the at least two elongated materials of each of the twisted strand materials while removing the twist therefrom; and then retwisting together the successive sections of each of the strand materials about the mutual axis to reform a plurality of twisted strand materials; and associated together successive sections of the plurality of strand materials while imparting a lay thereto.
 4. The method of claim 3, wherein the disassociating and retwisting of the elongated materials includes the steps of: moving successive sections of the at least two elongated materials of each of the strand materials along a separate path, at least portions of the separate paths being spaced generally equally circumferentially about the mutual axis; while revolving disassociated successive sections of the strand materials being advanced along the separate paths about the associated predetermined path to remove the twist therefrom; and converging together the successive sections of each of the at least two elongated materials of each of the strand materials in a downstream direction to reform a plurality of twisted strand materials.
 5. The method of claim 4, wherein each of the strand materials includes a conductor pair, the conductors being twisted together, then separated to remove the twist therefrom and subsequent thereto being retwisted and stranded with other cable pairs to form a cable unit.
 6. The method of claim 5, wherein the cable unit is bound together and then taken up on a reel.
 7. The method of claim 5, wherein the twisting together of successive sections of each of the conductor pairs includes the steps of: supporting rotatably a pair of supply reels, each of the supply reels having convolutions of a conductor wound thereon; withdrawing the conductors from each of the supply reels in a first direction generally opposite to the direction of take-up; then advancing the associated conductors generally in the direction of take-up along an arcuate path circumscribing the reels; and revolving successive sections of the associated conductors of each pair in the arcuate path about the reels to impart a twist to the two conductors generally in the vicinity of the change in direction from that opposite to take-up to the same direction as take-up, the direction of revolution of the successive sections of the twisted pair being in the same direction of revolution as the revolution of the successive sections of the conductor paiRs being advanced subsequently along the separate paths.
 8. The method of claim 7, wherein one twist length is imparted to each of the conductor pairs and then removed and wherein the retwisting includes imparting two twists per same length of each of the conductor pairs.
 9. The method of claim 8, wherein the twist length of each of the plurality of conductor pairs is different from one another.
 10. A method of twisting and stranding cable pairs in a tandem operation, which comprises the steps of: mounting each of a plurality of supply of conductor pairs along an associated axis at an upstream portion of the axis; the axes associated with the conductor pairs arrayed about and converging downstream toward a centerline; withdrawing successive sections of each of the pairs of conductors from the associated supply in an upstream direction generally along the associated axis; advancing successive sections of each twisted pair of conductors in a downstream direction opposite to the direction of withdrawal; while revolving successive sections of each of the twisted pairs about the axis to impart a twist to each pair of the conductors; continuing to advance the successive sections of each twisted pair further along the axis; separating the conductors of each conductor pair and advancing each conductor of each conductor pair along a separate path, at least portions of the separate paths being spaced generally equally circumferentially about the associated axis; revolving the successive sections of each separated pair about the associated axis to remove the twist imparted to each pair of the conductors, the direction of revolution of the separated pair being the same as the direction of revolution of the twisted pair; while reassociating the strands into a conductor pair by converging the successive sections of the associated conductor pair toward the associated axis in the downstream direction to retwist together the conductors of each pair; converging each of the retwisted conductor pairs toward the centerline while rotating the plurality of pairs to impart a lay thereto and strand the pairs into successive sections of a cable unit; and taking up the successive sections of the cable unit.
 11. The method of claim 10, wherein the twist is removed from each of the conductor pairs by revolving the separated strands of each pair about the associated axis at a predetermined speed relative to the revolving of the twisted pair about the pair axis.
 12. The method of claim 11, wherein the successive sections of the separated conductors of each pair are revolved about the associated pair axis at an orbital speed double that of the revolution of the twisted pair about the associated pair axis.
 13. A method of twisting together successive sections of associated portions of a strand material, which includes the steps of: advancing successive sections of the strand material along a predetermined path; imparting a twist to the successive sections of the associated portions of the strand material; disassociating the successive sections of the associated portions of the strand material while removing the twist therefrom; and retwisting together the successive sections of the portions of the strand materials to associate together the successive sections thereof into a strand material.
 14. A method of twisting successive sections of a conductor pair, which comprises the steps of: advancing successive sections of the conductors from a supply thereof along a predetermined path; imparting a twist to the successive sections of the conductor pair to associate the successive sections of one of the conductors with the successive sections of the associated conductor; moving successive sections of each of the conductors along a separate path, at least portions of the separate paths being spaced generally equally circumferentially about the predetermined path; revolving the successive sectioNs of the conductors being advanced along the separate paths about the predetermined path to remove the twist from the conductor pair; while converging the successive sections of the conductors in a downstream direction to cause a retwisting of the successive sections of the conductors.
 15. The method of claim 14, wherein the point of convergence of the conductors of the pair is varied in a predetermined manner to vary the twist length along the pair.
 16. The method of claim 15, wherein the variation is a random one.
 17. A method of twisting successive sections of associated portions of a strand material, which comprises: advancing the successive sections of the associated portions of the strand material in a first direction; imparting an initial twist per length to the successive sections of associated portions of the strand material; advancing the successive sections of the twisted strand material in a second direction generally opposite to the first direction and then along an axis; separating the successive sections of the associated portions of the strand material while revolving the successive separated sections about the axis to remove the initial twist imparted to the successive sections of the strand material; and then reimparting a twist to the successive sections of the strand material.
 18. The method of untwisting and retwisting a twisted pair of conductors as set forth in claim 17, wherein the reimparting of the twist is accomplished by converging the successive sections of each of the two conductors having portions thereof revolved about the axis in a downstream direction toward a point on the axis.
 19. The method of claim 18, wherein the angle of convergence along the axis is varied randomly to vary the twist length of the conductor pair.
 20. The method of claim 18, wherein the twist length of the reimparted twist is half that of the initial twist length.
 21. An apparatus for tandemized twisting and stranding indefinite lengths of strand materials, which includes: means for advancing successive sections of each of a plurality of strand materials along an associated predetermined path; means for imparting a twist to successive sections of portions of each of the plurality of strand materials while advancing each of the strand materials along the associated predetermined path; means for disassociating successive sections of the twisted portions of each of the strand materials and for removing the twist therefrom; means for retwisting together the successive sections of the portions of each of the strand materials; and means for stranding together the successive sections of the plurality of strand materials.
 22. An apparatus for tandemized twisting and stranding indefinite lengths of strand materials, which includes: means for advancing successive sections of each of a plurality of strand materials along an associated predetermined path; means for imparting a twist to successive sections of portions of each of the plurality of strand materials about a mutual axis while advancing each of the strand materials along the associated predetermined path to form a plurality of twisted strand materials; means for moving the successive sections of the portions of each of the strand materials along a separate path, at least portions of the separate paths being spaced generally equally circumferentially about the associated mutual axis; means for revolving the successive sections of the portions of each of the strand materials being advanced along the separate paths about the associated predetermined path to remove the twist therefrom and to reimpart a twist to the successive sections of the portions of each of the strand materials downstream of the revolving means; means downstream of the revolving means for converging the successive sections of the portions of each of the strand materials subsequent to the successive sections being advanced along the separate pathS about the associated predetermined path to facilitate the retwisting of each of the strand materials; and means for stranding together the successive sections of the plurality of strand materials.
 23. The apparatus of claim 22, which also includes means for varying the angle of convergence of the associated portions of each of the strand materials to vary randomly the twist length.
 24. The apparatus of claim 22, wherein the means for separating the successive portion of the portions of the strand materials includes: a pair of sheaves; and means mounting the sheaves for rotation about individual parallel axes spaced one on each side of the predetermined path and being transverse of the predetermined path.
 25. An apparatus for twisting together a pair of conductors drawn from supply reels to form a twisted pair and for stranding together a plurality of twisted pairs into a cable unit, which includes: means for supporting a plurality of pairs of the supply reels; means for withdrawing the pair of conductors from each pair of supply reels; means revolved about an axis of each of the supporting means for imparting a twist to a pair of conductors as the conductors are withdrawn in a direction generally along the axis; means for revolving the imparting means about the axis; means interposed between the revolving means and the imparting means for selectively changing the rotational speeds of the imparting means; means rotatably mounted about each of the axes and connected to the revolving means for guiding each of the conductor pairs away from the twist imparting means; means connected to the guiding means and mounted rotatably for separating and guiding the conductors of each twisted pair along separate paths, at least portions of each of the separate paths being spaced generally equally circumferentially about the associated axis and being revolvable about the associated axis; means connecting the revolving means and the separating means for moving the separating means about the associated axis at a velocity relative to the velocity of the imparting means to remove the twist from the associated conductor pair; means cooperating with and aligned with the separating means for reimparting a twist of a predetermined length to each of the conductor pairs; means for imparting a lay to the plurality of conductor pairs to strand the plurality of conductor pairs together into a cable unit; means for applying a binder to the cable unit; and means for taking up the cable unit.
 26. The apparatus of claim 25, wherein the moving means which connects the revolving means and the separating means causes the rotational speed of the separating means to be twice that of the imparting means and in the same direction as that of the imparting means.
 27. An apparatus for twisting a pair of conductors, which comprises: means for imparting a predetermined length twist to each of a plurality of pairs of conductors, means for separating the conductors of each conductor pair and for untwisting the conductors of each of the conductor pairs; and means for retwisting each of the conductor pairs.
 28. An apparatus for twisting a pair of conductors, which includes: means for advancing successive sections of each of the conductors along a predetermined path; means for imparting a twist having a predetermined length to successive sections of the conductor pair about a mutual axis; means for moving successive sections of each of the conductors along a separate path, at least portions of the separate path being spaced generally equally circumferentially about the mutual axis; means spaced a predetermined distance downstream from the moving means for receiving the successive sections of the conductors to converge the conductors; and means interposed between the moving means and the receiving means for revolving successive sections of the conductors being advanced along the Separate paths about the predetermined path to remove the twist therefrom and for reimparting a twist thereto about the mutual axis as the conductors are converged in the receiving means.
 29. An apparatus for twisting together each of a plurality of pairs of conductors, which includes: a plurality of reel support cradles arranged about a central axis, each of the cradles being free-floating and having an axis inclined toward the central axis at a point downstream thereof, the plurality of axes of the cradles converging at the point, a reel support cradle positioned along the central axis of the plurality thereof; a flier bow associated with each of the cradles and having facilities for guiding the conductors from the supply reels thereof for imparting a predetermined length of twist thereto; means for revolving the flier bow about the axis of the cradle; means for driving each of the flier bows at a different angular velocity than the others; means mounted rotatably and aligned with the flier bow for guiding the twisted pair downstream of the cradle along the cradle axis extended downstream; means connected to a downstream end of each of the guiding means for separating each of the twisted pairs and for guiding the separated conductors along separate paths downstream thereof, the separate paths of each pair having at least portions thereof spaced on opposite sides of the extended cradle axis; means driving the guiding and separating means in the same rotational direction as the associated flier bows and at an angular velocity greater than that of the associated flier bows for revolving the separated successive sections of the conductors of each pair about the associated extended cradle axis to untwist the successive sections of each of the conductor pairs upstream thereof and subsequently retwisting the successive sections of the conductor pairs downstream thereof; and means for converging the separated successive sections of each of the pair of conductors to facilitate the imparting of a twist to each pair of the conductors.
 30. The apparatus of claim 29, wherein the separating means is driven at an angular velocity twice that of the flier bows.
 31. An apparatus for withdrawing a plurality of pairs of conductors from supply reels and for imparting a precise uniformly distributed twist thereto, which comprises: a plurality of freely rotatable cradles, with each of the cradles supporting two of the supply reels, the plurality of cradles being arrayed about a longitudinal axis with the cradles converging toward a point on the longitudinal axis downstream of the cradles, a cradle positioned upstream of the plurality of cradles; a flier bow associated with each of the cradles and having facilities for guiding a pair of the conductors from the cradle to the upstream end thereof to a downstream end thereof, means for mounting the upstream and downstream ends of the flier bow to facilitate orbital motion of the flier bow about the axis of the associated cradle, means mounted rotatably on the mounting means at each end of each of the flier bows for imparting a first twist length to the conductor pair at the upstream end of the flier bow and tending to impart a second twist per length at the downstream end thereof; means receiving the twisted pair of conductors and aligned with the axis of each of the cradles for guiding the associated twisted pair downstream, means connected to each of the flier bows and to the associated guiding means for driving each of the flier bows at a predetermined rotational speed and for driving each of the associated guiding means at a predetermined rotational speed, means connected to each of the guiding means and designed to be turned rotatably therewith for separating the pair of conductors to permit the conductors to be advanced along separate paths having at least portions thereof spaced circumferentially about the axis of the cradle as extended downstReam thereof, the rotation of the separating means causing the successive sections of each of the conductor pairs being advanced along separate paths to be revolved about the associated cradle axes to untwist the conductor pair; means for advancing each of the pair of conductors from the flier bows through the guiding and separating means, and means downstream of each of the separating means for converging the separated successive sections of the associated conductor pair as the conductor pair is advanced therethrough to facilitate retwisting thereof, the successive sections of each of the conductor pairs being revolved about the associated cradle axis including the successive sections being advanced into and through the converging means.
 32. The apparatus of claim 31, wherein the means mounted at each end of the flier bow includes a pair of rotatably mounted sheaves, the first twist length being imparted to the conductor pairs generally in the vicinity of one of the upstream pair of sheaves and the second twist per length, in the vicinity of the downstream pair of sheaves.
 33. The apparatus of claim 31, wherein the second twist per length is prevented from being imparted to each of the conductor pairs by increasing the rotational speed of the guiding means and separating means over that of the flier bows.
 34. The apparatus of claim 33, wherein the rotational speed of each of the separating means being twice that of the associated one of the flier bows, the drive system being capable of being programmed to drive each of the flier bows and associated separating means at a different speed.
 35. The apparatus of claim 33, wherein the separating means includes two sheaves mounted on spaced parallel axes for revolution about the axis of revolution of the flier bow, each of the sheaves having two grooves, with one of the conductors being advanced over one groove of one sheave, then over one groove of the other sheave, the other conductor being advanced over the other groove of the second sheave and then over the other one of the grooves of the other sheave.
 36. The apparatus of claim 33, wherein each of the converging means is a tube which is moved reciprocally along the axis of the cradle at random to impart varying final twist to the conductor pair.
 37. The apparatus of claim 33, wherein the converging means is positioned in a predetermined distance downstream of the separating means.
 38. A device for imparting a precise uniformly distributed twist to at least two elongated materials, which comprises: means positioned along a predetermined path and engaging the at least two elongated materials twisted together for separating and guiding the two elongated materials along separate paths symmetrical with respect to an axis, means spaced along the predetermined path from the guiding means and cooperating with the guiding means for receiving separated successive sections of the elongated materials; and means for revolving the guiding means about the predetermined path to remove the twist from and disassociate the two elongated materials and for reimparting a twist to the at least two elongated materials about a mutual axis.
 39. The device of claim 38, for imparting a precise uniformly distributed twist to a pair of conductors, wherein the separating means includes a rotatably mounted spinner having two bores formed therethrough, the bores being parallel to one another and spaced on opposite sides of the axis.
 40. The device of claim 38, wherein the separating means includes a channel mounted for rotation about the axis and having the longitudinal axis thereof parallel to the axis, the channel having an upstanding plate positioned therein with one conductor on each side of the plate.
 41. A device for untwisting a pair of conductors which have been twisted together about a mutual axis and for retwisting the conductors, which includes: means for advancing a twisted pair of conductors along a predetermined path; a block positioned along the predetermined path having a hole formed in an upstream end thereof for receiving successive sections of the twisted pair of conductors, the block also having a pair of side plates extending downstream from the block; a first sheave having a pair of grooves; means mounting rotatably the first sheave between the side plates with the axis of rotation thereof being generally normal to the predetermined path along which the successive sections of the strand material are being advanced; a second sheave having a pair of grooves, means mounting rotatably the second sheave between the side plates with the axis thereof normal to the predetermined path and spaced from the axis of the first sheave, means connected to the block and aligned with the central hole therein for moving rotatably the block at a predetermined rate of speed to revolve the sheaves about the predetermined path and for guiding the previously twisted pair of conductors into the block; and means spaced a predetermined distance downstream of the block along the predetermined path and aligned with the block for receiving the conductors, the conductors of the twisted pair being separated as the conductors of the twisted pair are advanced through the guiding means with the one conductor being advanced around one of the grooves in the first sheave and then around a groove in the second sheave and with the other conductor being advanced around the other groove of the second sheave and then around the other groove of the first sheave, the successive sections of the separated conductors then being advanced, while being revolved about the predetermined path, into converging engagement within the receiving means to permit retwisting of the pair of conductors about the mutual axis.
 42. A system for paying off one conductor from one supply reel and another conductor from another supply reel and for twisting together the pair of conductors, a cradle for holding the pair of supply reels, means for driving the supply reels to pay off the conductors therefrom; support means positioned at each end of the cradle and mounted rotatably for supporting freely rotatably the cradle about an axis therethrough, the support means being capable of being rotated independently of the cradle; a flier bow connected at the ends thereof to the support means, the flier bow designed to be revolved about the axis as the support means are rotated thereabout, a drive shaft extending externally of the support means, means for turning the drive shaft at a predetermined rate of speed, means for transmitting the motion of the drive shaft to each of the support means to turn rotatably the support means; and means mounted on the support means for controlling the operation of the driving means to maintain a constant tension in the elongated materials being payed out.
 43. The system of claim 42, wherein the tension control means includes: a sheave, means mounting the sheave for pivotal movement, means biasing the mounting means in a first direction, a first gear mounted on the mounting means and having the teeth thereof formed in an arcuate path to follow the path of pivotal movement, a second gear mounted on the support means and being in meshing engagement with the first gear, means connected to the second gear for controlling the drive means to increase or decrease the speed of paying out the conductors as the sheave is moved pivotally in the first direction or a direction opposite thereto. 